Nitrogen-doped graphene quantum dots( N-GQDs)exhibiting excitation-independent green fluorescence emission( 536 nm) was facilely synthesized. The as-prepared N-GQDs showed a highly selective fluorescence quenching res...Nitrogen-doped graphene quantum dots( N-GQDs)exhibiting excitation-independent green fluorescence emission( 536 nm) was facilely synthesized. The as-prepared N-GQDs showed a highly selective fluorescence quenching response toward Hg2 + with a linear range of 0. 1-30. 0 μmol/L and detection limit of50 nmol/L. Based on the high affinity of biothiols( such as cysteine)toward Hg2 +, the quenched fluorescence of N-GQDs could be recovered upon addition of biothiols,and thereby a new fluorescence turn-on probe for cysteine detection was further developed. The linear range and detection limit for cysteine were found to be 0. 1-12. 5 μmol/L and 46 nmol/L,respectively. The present fluorescent probe worked well in a physiological pure water medium,allowing a fluorescence imaging of cysteine in living cells.展开更多
目的比较不同炮制条件对地骨皮化学成分的影响,优选饮片炮制方法。方法采用HPLC-IT-TOF/MS;ZORBAX SB-Aq C_(18)色谱柱;流动相为0.1%甲酸水溶液-乙腈梯度洗脱;柱温40℃;流速0.3 mL/min;进样体积5μL;电喷雾离子源(Electrospray Ionizati...目的比较不同炮制条件对地骨皮化学成分的影响,优选饮片炮制方法。方法采用HPLC-IT-TOF/MS;ZORBAX SB-Aq C_(18)色谱柱;流动相为0.1%甲酸水溶液-乙腈梯度洗脱;柱温40℃;流速0.3 mL/min;进样体积5μL;电喷雾离子源(Electrospray Ionization,ESI),正、负离子模式下扫描,根据相对分子质量和碎片离子等质谱信息,结合文献信息以及数据库鉴定化学成分,并以各成分的离子峰面积比作为不同炮制品的变化指数进行比较。根据鉴定结果将地骨皮5种主要活性成分的相对含量进行逼近理想解排序法分析(technique for order preference by similarity to ideal solution,TOPSIS),以客观评价经不同炮制方法所得地骨皮的品质。结果共鉴定23种化合物,其中亚麻酸在烘干80℃、焙干100℃时消失,甜菜碱在淘洗2次后消失。地骨皮在不同炮制方法下各成分含量差异较大,随着淘洗次数的增加,地骨皮中成分含量迅速下降;甜菜碱含量随着烘制温度的升高而升高,相反咖啡酰丁二胺含量会随着烘制温度的升高而降低;地骨皮甲素、地骨皮乙素均在50℃烘干时含量最高,绿原酸晒干时含量最高。通过对7种地骨皮样品进行综合评价分析,发现30℃晒干,淘洗1次(S1)为最佳炮制方式。结论地骨皮各炮制品中化合物种类和成分均发生变化;S1为最佳炮制方式。阐明了经不同炮制方法后地骨皮成分变化规律,并为地骨皮质量控制和评价奠定基础。展开更多
基金Shanghai Municipal Natural Science Foundation,China(No.16ZR1401700)Innovation Experiment Project for University Student of Donghua University,China(No.hsxy10201708)
文摘Nitrogen-doped graphene quantum dots( N-GQDs)exhibiting excitation-independent green fluorescence emission( 536 nm) was facilely synthesized. The as-prepared N-GQDs showed a highly selective fluorescence quenching response toward Hg2 + with a linear range of 0. 1-30. 0 μmol/L and detection limit of50 nmol/L. Based on the high affinity of biothiols( such as cysteine)toward Hg2 +, the quenched fluorescence of N-GQDs could be recovered upon addition of biothiols,and thereby a new fluorescence turn-on probe for cysteine detection was further developed. The linear range and detection limit for cysteine were found to be 0. 1-12. 5 μmol/L and 46 nmol/L,respectively. The present fluorescent probe worked well in a physiological pure water medium,allowing a fluorescence imaging of cysteine in living cells.
文摘目的比较不同炮制条件对地骨皮化学成分的影响,优选饮片炮制方法。方法采用HPLC-IT-TOF/MS;ZORBAX SB-Aq C_(18)色谱柱;流动相为0.1%甲酸水溶液-乙腈梯度洗脱;柱温40℃;流速0.3 mL/min;进样体积5μL;电喷雾离子源(Electrospray Ionization,ESI),正、负离子模式下扫描,根据相对分子质量和碎片离子等质谱信息,结合文献信息以及数据库鉴定化学成分,并以各成分的离子峰面积比作为不同炮制品的变化指数进行比较。根据鉴定结果将地骨皮5种主要活性成分的相对含量进行逼近理想解排序法分析(technique for order preference by similarity to ideal solution,TOPSIS),以客观评价经不同炮制方法所得地骨皮的品质。结果共鉴定23种化合物,其中亚麻酸在烘干80℃、焙干100℃时消失,甜菜碱在淘洗2次后消失。地骨皮在不同炮制方法下各成分含量差异较大,随着淘洗次数的增加,地骨皮中成分含量迅速下降;甜菜碱含量随着烘制温度的升高而升高,相反咖啡酰丁二胺含量会随着烘制温度的升高而降低;地骨皮甲素、地骨皮乙素均在50℃烘干时含量最高,绿原酸晒干时含量最高。通过对7种地骨皮样品进行综合评价分析,发现30℃晒干,淘洗1次(S1)为最佳炮制方式。结论地骨皮各炮制品中化合物种类和成分均发生变化;S1为最佳炮制方式。阐明了经不同炮制方法后地骨皮成分变化规律,并为地骨皮质量控制和评价奠定基础。